Ostracoda and Foraminifera of Tidal Rivers. 13 
beset with minute rounded papille. Colour (of dried spe- 
cimens) very slight, whitish. Lucid spots narrow, cres- 
centic. Length +; meh. Animal unknown. 
Hab. Site of Whittlesea Mere. Only one or two perfect spe- 
cimens obtained. 
-Cypris tumefacta, nov. sp. (Pl. IV. figs. 4-6.) 
Carapace (of the female?) very tumid, seen from the side, 
subreniform, highest in the middle; greatest height equal- 
ling rather more than half the length; extremities rounded, 
sloping steeply above the middle: superior margin very 
boldly i. rising almost to a point in the middle, infe- 
rior gently sinuated in the middle. Seen from above, 
broadly ovate, suddenly and acutely mucronate in front, 
well rounded behind; sides subparallel, greatest width 
situated in the middle, and somewhat greater than the 
height: end view subrhomboidal, pointed above, broadl 
rounded below, sides excessively convex. Shell perfectly 
smooth, opaque white. Length > inch. Animal un- 
Hab. Warn burn and river Coquet, Northumberland. 
If viewed only from the side, this species might not un- 
reasonably be suspected to belong to C. virens or perhaps C. : 
(ncongruens; but when seen in any othe rdirection, this simi- 
larity entirely disappears: no species possesses a more cha- 
racteristic or well-marked contour when looked upon from 
above. In the Warn burn about half a dozen specimens were 
found, in the river Coquet only one. 
Cypris fretensis, nov. sp. (PL. IV. figs. 7-9.) 
width equal to about two-thirds of the ae end view 
ovate, pointed above, broadly rounded below. Valves 
smooth, minutely and closely punctate ; right valve crenu- 
lated in front and on the posterior portion of the ven 
margin; the left valve has a row of small tubercles parallel 
to and a little within the anterior border: the margins of 
the valves are considerably incurved along the posterior 
